Some communication apparatus according to the related art are controlled to perform predetermined operations in a state in which they are disposed on a rotary body (for example, see International Patent Publication No. 2010/067838 (Patent Document 1)).
When radio communication with a communication apparatus disposed on a rotary body is performed using the millimeter waveband, electric waves are transmitted using structures such as a column provided in the middle of the rotary body, e.g., using the interior of the column as a waveguide.